Flora of China 12: 327–329. 2007.

17. PTEROSPERMUM Schreber, Gen. Pl. 2: 461. 1791, nom. cons. 翅子树属 chi zi shu shu Trees or shrubs, stellate velutinous or scurfy and scaly. Leaves simple; stipules linear to palmately fimbriate, sometimes forming nectaries, caducous; petiole short; leaf blade lobed or not, leathery, base often oblique, margin entire or serrate, apex some- times truncate; juvenile leaves sometimes much larger, petiole long, leaf blade often with peltate base and prominently palmately lobed. Inflorescence axillary, 1-flowered or cymose and 1–5-flowered. Flowers bisexual; epicalyx lobes usually 3, usually distant from calyx, entire, fimbriate, or palmately lobed, rarely absent, caducous. Calyx 5(or 6)-lobed, divided nearly to base, usually spreading to ± reflexed, caducous. Petals 5, white or yellow, often erect. Androgynophore present, very short, glabrous. Stamens 15, in 5 groups of 3 alternating with staminodes; filaments connate into tube, free at top; anthers 2-celled, cells parallel, connective pointed; staminodes 5, filiform, longer and thicker than filaments. Ovary 5-locular; ovules 4–22 per locule; style clavate or filiform; stigma longitudinally 5-grooved. Fruit a schizocarp, cylindric or ovoid, angular or rounded, usually woody, sometimes leathery, dehiscent into 5 loculicidal mericarps when mature. Seeds 2 to many per locule, with long, oblong, membranous wing; endosperm scanty or absent; cotyledons usually plicate, simple. 2n = 38.

Between 18 and 40 species: tropical and subtropical Asia; nine species (five endemic) in China.

Sterculia peltata G. Don (Gen. Hist. 1: 517. 1831), based on material from China, has long petiolate 5-lobed peltate leaves that are abaxially puberulent and adaxially glabrous, and has stems and petioles with a white tomentum. The leaf form is much more suggestive of juvenile material of Pterospermum than a species of Sterculia but the white indumentum is difficult to match with the species known from China. Key to flowering material (flowers not known for Pterospermum yunnanense) 1a. Leaf blade 24–34 × 14–29 cm; sepals to 9 cm ...... 1. P. acerifolium 1b. Leaf blade 4.5–18 × 1.5–11 cm; sepals 1.5–6.5 cm. 2a. Petals obovate, ca. 2.8 cm wide ...... 3. P. kingtungense 2b. Petals linear to oblanceolate, 0.4–1.1 cm wide. 3a. Leaf blade of mature trees very variable, usually oblique, lobes very irregular ...... 2. P. proteus 3b. Leaf blade of mature trees uniform, usually bilaterally symmetrical, entire or with apex regularly 3–5-lobed. 4a. Leaf blade of mature trees broadest above middle, apex 3–5-lobed ...... 4. P. truncatolobatum 4b. Leaf blade of mature trees oblong, elliptic, or broadest at or below middle, apex not lobed. 5a. Epicalyx lobes linear-divided; pedicel 3–5 cm ...... 9. P. lanceifolium 5b. Epicalyx lobes entire; pedicel to 1.5 cm. 6a. Leaf blade base obtuse or truncate, rarely shallowly obliquely cordate; sepals 2.5–2.8 × ca. 0.4 cm ...... 8. P. heterophyllum 6b. Leaf blade base obliquely cordate or rounded; sepals 3.5–4.5 × 0.25–0.4 cm. 7a. Leaf blade base obliquely cordate; sepals ca. 4.5 × 0.4 cm; androgynophore ca. 2 cm ...... 6. P. niveum 7b. Leaf blade base obliquely rounded; sepals ca. 3.5 × 0.25 cm; androgynophore ca. 0.8 cm ...... 7. P. menglunense Key to fruiting material (fruits not known for Pterospermum kingtungense) 1a. Capsule 3–6 cm. 2a. Capsule apex 3–5 mm, beaked ...... 2. P. proteus 2b. Capsule apex obtuse. 3a. Small trees, to 5 m tall; branchlets gray puberulent when young ...... 5. P. yunnanense 3b. Large trees, 20–25 m tall; branchlets yellow-brown pilose or velutinous. 4a. Petiole 1–2 cm, leaf blade 7–15 × 3–10 cm; capsule stipe robust, 1–1.5 cm ...... 8. P. heterophyllum 4b. Petiole ca. 0.5 cm, leaf blade 5–9 × 2–3 cm; capsule stipe slender, 3–5 cm ...... 9. P. lanceifolium 1b. Capsule 8–15 cm. 5a. Leaf blade 24–34 × 14–29 cm, base not oblique ...... 1. P. acerifolium 5b. Leaf blade 4.5–18 × 1.5–11 cm, base oblique. 6a. Leaf blade apex truncate and 3–5-lobed; capsule prominently 5-angled, ca. 12 × 7 cm ...... 4. P. truncatolobatum 6b. Leaf blade apex acuminate or caudate; capsule rounded, 8–10 × ca. 3 cm. 7a. Branchlets yellow stellate tomentose when young; capsule glabrous, apex beaked ...... 6. P. niveum 7b. Branchlets shortly gray-white woolly when young; capsule ?hairy, apex acute ...... 7. P. menglunense

1. Willdenow, Sp. Pl. 3: 729. 翅子树 chi zi shu 1800. Big trees; bark smooth. Branchlets densely velutinous Flora of China 12: 327–329. 2007. when young. Stipules linear; petiole robust, striate; leaf blade 4.8 × 2.8 cm, stellate puberulent, especially at base, base nearly orbicular or oblong, sometimes ± lobed, 24–34 × 14–29 clawed, apex rounded. Androgynophore ca. 6 mm; filaments cm, leathery, abaxially densely yellowish and gray stellate velu- glabrous, apex of connective pointed and caudate; staminodes tinous, adaxially sparsely hairy or glabrous, base cordate, mar- linear-clavate, ca. 3.5 cm, glabrous, upper part densely verru- gin entire or crenate, apex truncate, nearly rounded, or pointed; cose. Ovary ovoid, densely yellowish brown tomentose; style juvenile leaves palmately lobed, peltate. Flowers solitary, fra- hairy; stigmas free but twisted together. Capsule not seen. grant; epicalyx lobes fimbriate or palmately divided. Sepals ● Forested valleys on limestone; 1400–1500 m. SW Yunnan linear-oblong, ca. 9 × 0.7 cm, abaxially densely yellow-brown (Jingdong). stellate velutinous, adaxially white villous. Petals white, linear- oblong, slightly cuneate, slightly shorter than sepals, glabrous. Pterospermum kingtungense is easily distinguished from other Staminodes clavate, hairy. Ovary oblong, 5-angular; ovules species by its much broader, obliquely obovate petals, ca. 2.8 cm many per locule. Capsule woody, cylindrical, stipitate, ob- wide, with a rounded apex. It is classified as “Critically endangered” in scurely 5-grooved, 10–15 × 5–5.5 cm, reddish brown velu- the IUCN Red List because its very small population is in an unpro- tinous, glabrescent, base tapering, apex rounded. Seeds many tected area subject to regular cutting. per locule, obliquely ovate, flat, wing large and thin, brown, 4. Pterospermum truncatolobatum Gagnepain, Notul. Syst. smooth. (Paris) 1: 84. 1909.

Forested slopes; 1200–1700 m. S Yunnan [Bangladesh, Bhutan, 截裂翅子树 jie lie chi zi shu India, Laos, Malaysia, Myanmar, Nepal, Thailand].

Pterospermum acerifolium is grown as an ornamental. Trees, to 16 m tall; bark black, striate. Branchlets densely yellow-brown stellate tomentose when young, becoming gray- 2. Pterospermum proteus Burkill, Bull. Misc. Inform. Kew white or yellowish gray stellate tomentose or nearly glabrous. 1901: 138. 1901. Stipules palmately 3–5-fimbriate, densely hairy, caducous; peti- ole robust, 4–12 mm; leaf blade oblong-obovate in outline, usu- 变叶翅子树 bian ye chi zi shu ally irregularly lobed, 8–16 × 3.5–11 cm, leathery, abaxially Small trees or shrubs, to 6 m tall. Branchlets densely white densely gray-white or yellow-brown stellate tomentose, adax- and yellowish brown puberulent. Leaf blade variously shaped, ially glabrous or minutely hairy along midrib, base cordate or nearly orbicular, or broadly oblong in outline, usually oblique, obliquely cordate, apex truncate and 3–5-lobed, central lobe sometimes irregularly lobed, 5–11 × 2–5.5 cm, abaxially acute or acuminate, 1–2 cm. Flowers solitary, nearly sessile; densely red-brown puberulent, adaxially red-brown puberulent epicalyx lobes fimbriate. Sepals linear, relatively thick, 4.5–6.5 and glabrescent, base shallowly obliquely cordate or peltate, × ca. 0.4 cm, abaxially densely brown tomentose, adaxially sil- margin entire or irregularly lobed, lobes obtuse or crenate, apex very white villous. Petals linear-falcate, 3–6 × 0.4–0.5 cm, base acuminate, obtuse, or truncate; juvenile leaves palmately 7- tapering. Stamens ca. 3.5 cm; staminodes filiform, ca. 5 cm, lobed, peltate. Flowers 1–4-fascicled; epicalyx lobes filiform, glabrous. Ovary ovoid, hairy. Fruiting pedicel to 8 mm; capsule ca. 2 mm. Sepals linear, ca. 1.5 × 0.15 cm, abaxially densely woody, ovoid or ovoid-cylindrical, prominently 5-angular and reddish brown puberulent. Petals linear, 1–1.2 cm, veins 7 or 8. 5-grooved, ca. 12 × 7 cm, densely brown stellate tomentose, Stamens slightly shorter than petals, almost free; staminodes ca. verrucose or not, base narrowed into 2–3 × ca. 1 cm stipe. 0.6 cm, hairy on upper part. Ovary ovoid, ca. 4 mm, densely Seeds 6–10 per locule, in 2 rows, 4–5.5 cm including wing, hairy. Capsule ovoid or ovoid-cylindrical, 5-angular or slightly wing linear, up to 4.4 cm, apex obtuse or truncate. Fl. Jul. foveolate, 3–4 cm, densely red-brown stellate tomentose, apex Dense forests on limestone; 300–500 m. SE Guangxi (Ningming, with 3–5 mm beak. Seeds ca. 3 cm including wing. Longzhou), SE Yunnan (Jinping) [N Vietnam]. ● Open forests on limestone; 900–1700 m. S Yunnan. 5. Pterospermum yunnanense H. H. Hsue, Acta Phytotax. 3. Pterospermum kingtungense C. Y. Wu ex H. H. Hsue, Sin. 15(1): 81. 1977. Acta Phytotax. Sin. 15(1): 81. 1977. 云南翅子树 yun nan chi zi shu 景东翅子树 jing dong chi zi shu Small trees, to 5 m tall. Branchlets gray puberulent when Trees, to 12 m tall; bark brown. Branchlets dark brown young. Leaf blades dimorphic: those of young trees and cop- puberulent. Stipules ovate, scalelike, entire, ca. 4 mm; petiole piced branches with petiole up to 24 cm, blade palmately 5- ca. 1 cm, densely brownish tomentose; leaf blade oblong-obo- divided, lobes nearly linear, ca. 16 × 11 cm, base peltate, apex vate in outline, usually irregularly lobed, 8–13.5 × 4.5–6 cm, acuminate; those of mature trees with petiole 1–1.5 cm, blade leathery, abaxially densely yellowish white stellate tomentose, oblong-obovate in outline, usually irregularly lobed, 6.5–8.5 adaxially glabrous, base rounded, truncate, or shallowly cor- cm, leathery, abaxially densely yellowish brown stellate puber- date, apex irregularly 3–5-lobed, bluntly acuminate. Flowers ulent, adaxially glabrous, base cordate or obliquely cordate, solitary, ca. 7 cm in diam., nearly sessile; epicalyx lobes ovate, apex truncate with obtuse acumen; lateral veins 5–6 per side of entire, hairy. Sepals linear to narrowly lanceolate, ca. 4.5 × 1.1 midrib. Flowers unknown. Capsule ovoid-ellipsoid, obscurely cm, abaxially densely dark brown tomentose, adaxially densely 5-angular and with 5 nearly flat foveolate spots, ca. 4 cm, yellow-brown tomentose. Petals white, obliquely obovate, ca. densely brown puberulent, base narrowed into ca. 6 mm stipe,

Flora of China 12: 327–329. 2007. apex obtuse. Seeds ca. 2.8 cm including wing, wing brown, Pterospermum menglunense, though found within a protected apex obtuse. area, is still treated as “Critically endangered” in the IUCN Red List because of the very small, fragmented population. ● Forests on limestone cliffs and summit ridges; 1400–1600 m. S Yunnan. 8. Pterospermum heterophyllum Hance, J. Bot. 6: 112. 1868.

Pterospermum yunnanense is classified as “Critically endangered” 翻白叶树 fan bai ye shu in the IUCN Red List because there are few mature individuals and regeneration is poor. Pterospermum levinei Merrill.

6. Pterospermum niveum S. Vidal, Revis. Pl. Vasc. Filip. 67. Trees, to 20 m tall; bark gray or gray-brown. Branchlets 1886. yellow-brown pilose. Petiole 1–2 cm, hairy; leaf blade oblong- ovate to oblong, 7–15 × 3–10 cm, abaxially densely yellow- 台湾翅子树 tai wan chi zi shu brown stellate pubescent, adaxially nearly glabrous; base ob- Pterospermum formosanum Matsumura. tuse, truncate or obliquely cordate, apex acute or acuminate; juvenile and coppice leaves: petiole ca. 12 cm, leaf blade pal- Trees, to 20 m tall. Branchlets yellow stellate tomentose mately 3–5-lobed, ca. 15 cm in diam., base conspicuously pel- when young and glabrescent. Stipules lanceolate, ca. 8 mm; tate, truncate or slightly rounded. Flowers solitary or in cymes petiole 0.5–1 cm, gray-yellow velutinous; leaf blade oblong or of 2–4; pedicel 0.5–1.5 cm; epicalyx lobes closely adnate to oblong-lanceolate, 12–18 × 3.5–7 cm, abaxially densely gray- calyx, scalelike. Sepals linear, up to 2.8 × 0.4 cm, both surfaces yellow velutinous, adaxially yellow velutinous near base of puberulent. Petals greenish white, oblanceolate, as long as se- petiole, basal veins 5, impressed adaxially and prominently pals. Androgynophore ca. 2.5 mm; staminodes filiform, slightly raised abaxially, base obliquely cordate, margin entire, apex longer than stamens. Ovary ovoid, villous; style glabrous. Cap- acuminate or caudate. Flowers solitary, 5–7 cm in diam. Sepals sule woody, cylindrical-ovoid, ca. 6 × 2–2.5 cm, yellow tomen- linear-lanceolate, ca. 4.5 × 0.4 cm, abaxially yellow-brown tose, base tapering into robust, 1–1.5 cm stipe, apex obtuse. Fl. velutinous, adaxially villous. Petals white, obovate, ca. 3.5 × autumn. 1.1 cm, apex obtuse. Staminodes filiform. Ovary ovoid, densely tomentose; style glabrous; stigma 5-lobed. Capsule cylindrical, ● Fujian, Guangdong, Guangxi, Hainan. or cylindrical-ellipsoid, 8–10 × ca. 3 cm, glabrous, apex acute and beaked. Seeds 3–4 cm including wing, apex obtuse. The roots of Pterospermum heterophyllum are of medicinal use. The epithet refers to the great contrast in form between juvenile and Lowland forests. S Taiwan [Philippines]. mature leaves but this is not unique to this species. Pterospermum niveum is possibly conspecific with P. c el eb i cu m 9. Pterospermum lanceifolium Roxburgh, Fl. Ind., ed. 1832, Miquel. The type of P. formosanum has not been seen but the type 3: 163. 1832 [“lanceaefolium”]. locality and protologue description strongly suggest that it belongs here. 窄叶半枫荷 zhai ye ban feng he The timber is valued commercially. Trees, to 25 m tall; bark yellow-brown or gray, striate. 7. Pterospermum menglunense H. H. Hsue, Acta Phytotax. Branchlets yellow-brown velutinous when young. Stipules 2–3- Sin. 15(1): 81. 1977. fimbriate, velutinous, longer than petiole; petiole ca. 0.5 cm; 勐仑翅子树 meng lun chi zi shu leaf blade lanceolate or oblong-lanceolate, 5–9 × 2–3 cm, abax- ially densely yellow-brown or yellow-white velutinous, adax- Trees, to 12 m tall. Branchlets shortly gray-white woolly ially glabrous, base oblique or obtuse, margins entire or with when young. Petiole 0.3–0.5 cm; leaf blade lanceolate or ellip- several teeth near apex, apex acuminate or acute. Flowers soli- tic-lanceolate, 4.5–12.5 × 1.5–4.8 cm, thickly papery, abaxially tary; pedicels 3–5 cm, articulate, velutinous; epicalyx lobes at densely yellowish brown stellate velutinous, adaxially glabrous middle of pedicel, 4- or 5-fimbriate or linear, 7–8 mm. Sepals or minutely sparsely puberulent, base obliquely rounded, apex linear, ca. 2 × 0.3 cm, both surfaces puberulent. Petals white, long acuminate or caudate-acuminate. Flowers solitary, subter- lanceolate, as long as sepals or slightly shorter, apex obtuse. minal; pedicel ca. 0.5 cm; epicalyx lobes long-pointed, entire, Staminodes filiform, longer than stamens, basally villous. ca. 6 mm. Sepals linear, 3.5–3.8 × ca. 0.25 cm, abaxially Ovary puberulent. Capsule woody, cylindrical-ovoid, ca. 5 × densely yellow-brown stellate tomentose, adaxially glabrous. 2 cm, yellow-brown tomentose, base tapering into slender, 3–5 Petals white, obovate, ca. 3 × 0.8 cm, glabrous, base tapering cm stipe, apex obtuse. Seeds 2–4 per locule, 2–2.5 cm including into narrow stalk, apex obtuse with acumen. Androgynophore wing. Fl. spring and summer. ca. 8 mm, glabrous. Stamens slightly shorter than staminodes; staminodes ca. 1 cm, glabrous. Ovary ovoid, ca. 4 mm, densely Dense or open forests, slopes, valleys; 800–900 m. Guangdong, yellowish brown tomentose. Capsule narrowly ellipsoid, ca. 8 SW Guangxi, S Yunnan [India, Malaysia, Myanmar, Vietnam]. cm, base tapering into 1–2 cm stipe, apex acute. Seeds ca. 3.5 cm including wing. Fl. Apr.

● Monsoon forests on limestone hills. S Yunnan (Xishuangban- na).

Flora of China 12: 327–329. 2007.